I'd thought, it would be handy to have a somehow accurate simulation tool to have an easy look at possible variants and optimizations.
I've been advised to possibly give AkAbak a try, after Hornresp and AJHorn did not seem to be a good choice.

Needed is a possibility to simulate a *distributed speakers arrangement* in pipes - and possibly add dipole behavior.

After some reading, AkAbak starts to make sense.
First, a most simple simu of the H-frame with only the front duct being modelled - looks definitely promising with respect to the measurements already taken (red trace):

I have a few ideas, but some questions first. Can you post the exact measurements of the test enclosure, external is fine, and wood thickness. Was the driver mounted as shown in the 3d shot? Where was the mic placed?

Originally Posted by soho54
(http://www.diyaudio.com/forums/software-tools/179399-simulating-deep-frame-dipoe-dfd-woofers-akabak-post2405527.html#post2405527)

Interesting experiment.

I have a few ideas, but some questions first. Can you post the exact measurements of the test enclosure, external is fine, and wood thickness. Was the driver mounted as shown in the 3d shot? Where was the mic placed?

Have arrived at something close to your script yesterday (except the "edge" diffraction statements I have not looked into yet) - but are still a little bit slow in verifying
:)

Thanks for your input - very much appreciated!

regardig "wood thickness" : don't bother, there is no need to get "precise" results - all this simus are meant to just get the trend
regarding "driver mounting" : yes exactly like shown (I have added cone depth in my simu but it does not make the heck of a difference - as expected)
regarding "mic placement" : measurements (right a mouth) also were done just to catch the trend of different arrangements - so no claim to be "absolutely precise"

I will be back with some plots and specific questions soon...

Nice overlay plot BTW, I have to learn how to do this easily...

Michael

soho54

21st December 2010 01:38 PM

You're welcome.

This should be close enough then. I find that adding a conical diaphragm isn't necessary below ~1kHz.

Well,I added conical mainly because it adds some un-symmetry in case of H-frame.

For doing the overlay "right", I'm not clever enough as it seems.
:(
As far as I understood there is a max of thee traces to be overlaid. Works if I drag and drop from one plot into the other, but does not work to immediately simulate into one plot only and - also does not work to get / keep the colors of traces adjusted.

Another problem I've come across - seems if I simu close to mouth - approaching 40cm in above example - SPL level sky rocks to several 100dB. Any idea?

Michael

mige0

22nd December 2010 03:55 PM

Quote:

Originally Posted by mige0
(http://www.diyaudio.com/forums/software-tools/179399-simulating-deep-frame-dipoe-dfd-woofers-akabak-post2407137.html#post2407137)

For doing the overlay "right", I'm not clever enough as it seems.

Boy this took me time !
:)
I always tried to *add* traces to a given plot window - better to just choose / select the scripted labels and every trace is then put into the upcoming plot at once...